internally there is one main difference between an SV 83 and EL84...grid number 3 isn't tied to the cathode like an EL 84...to test this tube as an EL84  would require wrapping a wire around pin 3 and pin 1 of this tube before inserting into yer tube tester first...Hope this helps you

@ Dave Thanks much for that info .  Assume this applies to the 6n15n tube as well?  I don't think I will do the wire mod though.  Any idea if testing as an EL84 could of damaged the tube?

What is sort of a reality check is I just dont remember what I may have discovered about testing these back more than 10 yrs ago.  

@Rivieraranch   I do realize there are no Ruskie settings every time I check. doh!    Doesnt stop me from checking  yet again every decade or so    being as I have original manuals and supplement for my antique tester.